“Subsidies on domestic oil consumption have been instrumental in driving a very material increase in domestic demand within OPEC and other oil-exporting countries over the last decade, “ Lewis explained.

“The fact that less oil has been finding its way on to global markets since 2005 is the main reason why crude prices have been rising,” he said.

Subsidies are concentrated in OPEC countries where, according to the International Energy Agency, consumption of oil has risen more than 56 percent in a decade.

Lewis believes this means a continued squeeze on supply, resulting in real crude oil prices rising further over the long term.